FBI releases images of Boston Marathon bombing evidence

Authorities investigating the deadly bombings at the Boston Marathon have recovered a piece of circuit board that they believe was part of one of the explosive devices, and also found the lid of a pressure cooker that apparently was catapulted onto the roof of a nearby building, an official said Wednesday.

Authorities investigating the deadly bombings at the Boston Marathon have recovered a piece of circuit board that they believe was part of one of the explosive devices, and also found the lid of a pressure cooker that apparently was catapulted onto the roof of a nearby building, an official said Wednesday.

A law enforcement official briefed on the investigation confirmed to The Associated Press that authorities have recovered what they believe are some of the pieces of the explosive devices. The official spoke on condition of anonymity because this person was not authorized to publicly discuss evidence in the ongoing investigation.

A person close to the investigation previously told AP the bombs consisted of explosives put in 1.6-gallon pressure cookers, one with shards of metal and ball bearings, the other with nails.

An unclassified bulletin was sent Tuesday evening to law enforcement agencies across the country and said that the bomb inside the backpack was an “improvised explosive device (IED)” made out of a common pressure cooker.

The FBI says the other explosive was in a metal container, but there wasn’t enough evidence to indicate that it was also a pressure cooker.

It was not known what was used to set off the two explosives that killed three people Monday and injured more than 170 others.